The International Review of Contemporary Law released its volume 6, no. 2, earlier this month. The theme of this journal is “77 Years of the United Nations Charter.” The Head, Dr. Keanu Sai, and Deputy Head, Professor Federico Lenzerini, of the Royal Commission of Inquiry that investigates war crimes and human rights violations committed in the Hawaiian Kingdom, each had an article published in the journal.

Dr. Sai’s article is titled “All States have a Responsibility to Protect their Population from War Crimes—Usurpation of Sovereignty During Military Occupation of the Hawaiian Islands.” Dr. Sai’s article opened with:

At the United Nations World Summit in 2005, the Responsibility to Protect was unanimously adopted. The principle of the Responsibility to Protect has three pillars: (1) every State has the Responsibility to Protect its populations from four mass atrocity crimes—genocide, war crimes, crimes against humanity and ethnic cleansing; (2) the wider international community has the responsibility to encourage and assist individual States in meeting that responsibility; and (3) if a state is manifestly failing to protect its populations, the international community must be prepared to take appropriate collective action, in a timely and decisive manner and in accordance with the UN Charter. In 2009, the General Assembly reaffirmed the three pillars of a State’s responsibility to protect their populations from war crimes and crimes against humanity. And in 2021, the General Assembly passed a resolution on “The responsibility to protect and the prevention of genocide, war crimes, ethnic cleansing and crimes against humanity.” The third pillar, which may call into action State intervention, can become controversial.

Rule 158 of the International Committee of the Red Cross Study on Customary International Humanitarian Law specifies that “States must investigate war crimes allegedly committed by their nationals or armed forces, or on their territory, and, if appropriate, prosecute the suspects. They must also investigate other war crimes over which they have jurisdiction and, if appropriate, prosecute the suspects.” This “rule that States must investigate war crimes and prosecute the suspects is set forth in numerous military manuals, with respect to grave breaches, but also more broadly with respect to war crimes in general.”

Determined to hold to account individuals who have committed war crimes and human rights violations throughout the Hawaiian Islands, being the territory of the Hawaiian Kingdom, the Council of Regency, by proclamation on 17 April 2019, established a Royal Commission of Inquiry (“RCI”) in similar fashion to the United States proposal of establishing a Commission of Inquiry after the First World War “to consider generally the relative culpability of the authors of the war and also the question of their culpability as to the violations of the laws and customs of war committed during its course.” The author serves as Head of the RCI and Professor Federico Lenzerini from the University of Siena, Italy, as its Deputy Head. This article will address the first pillar of the principle of Responsibility to Protect.

Professor Lenzerini’s article is titled “Military Occupation, Sovereignty, and the ex injuria jus non oritur Principle. Complying with the Supreme Imperative of Suppressing ‘Acts of Aggression or Other Breaches of the Peace’ à la carte?” After covering the Iraqi military occupation of Kuwait and the Russian military occupation of Ukraine, Professor Lenzerini’s article draws attention to the American military occupation of the Hawaiian Kingdom. Professor Lenzerini writes:

As a factual situation, the occupation of Hawai‘i by the US does not substantially differ from the examples provided in the previous section. Since the end of the XIX Century, however, almost no significant positions have been taken by the international community and its members against the illegality of the American annex­ation of the Hawaiian territory. Certainly, the level of military force used in order to overthrow the Hawaiian Kingdom was not even comparable to that employed in Kuwait, Donbass or even in Crimea. In terms of the il­legality of the occupation, however, this circumstance is irrelevant, because, as seen in section 2 above, the rules of international humanitarian law regulating military oc­cupation apply even when the latter does not meet any armed resistance by the troops or the people of the oc­cupied territory. The only significant difference between the case of Hawai‘i and the other examples described in this article rests in the circumstance that the former oc­curred well before the establishment of the United Na­tions, and the resulting acquisition of sovereignty by the US over the Hawaiian territory was already consolidated at the time of their establishment. Is this circumstance sufficient to uphold the position according to which the occupation of Hawai‘i should be treated differently from the other cases? An attempt to provide an answer to this question will be carried out in the next section, through examining the possible arguments which may be used to either support or refute such a position.

In the next section, Professor Lenzerini undermines the argument that international law in 1893 allowed the occupying State, in this case the United States, to have acquired the sovereignty of the Hawaiian Kingdom because the United States exercised effective control over the territory. He wrote:

The main argument that could be used to deny the illegality of the US occupation of Hawai‘i rests in the doctrine of intertemporal law. According to this doctrine, the legality of a situation “must be appraised […] in the light of the rules of international law as they existed at that time, and not as they exist today”. In other words, a State can be considered responsible of a violation of international law—implying the determination of the consequent “secondary” obligation for that State to restore legality—only if its behaviour was prohibited by rules already in force at the time when it was held. In the event that one should ascertain that at the time of the occupation of Hawai‘i by the US international law did not yet prohibit the annexation of a foreign territory as a consequence of the occupation itself, the logical conclusion, in principle, would be that the legality of the annexation of Hawai‘i by the United States cannot reasonably be challenged. In reality even this conclusion could probably be disputed through using the argument of “continuing violations”, by virtue of the violations of international law which continue to be produced today as a consequence of the American occupation and of its perpetuation. In fact, it is a general principle of international law on State responsibility that “[t]he breach of an international obligation by an act of a State having a continuing character extends over the entire period during which the act continues and remains not in conformity with the international obligation”.

However, it appears that there is no need to rely on this argument, for the reason that also an intertemporal-law-based perspective confirms the illegality—under international law—of the annexation of the Hawaiian Islands by the US. In fact, as regards in particular the topic of military occupation, the affirmation of the ex injuria jus non oritur rule predated the Stimson doctrine, because it was already consolidated as a principle of general international law since the XVIII Century. In fact, “[i]n the course of the nineteenth century, the concept of occupation as conquest was gradually abandoned in favour of a model of occupation based on the temporary control and administration of the occupied territory, the fate of which could be determined only by a peace treaty”, in other words, “the fundamental principle of occupation law accepted by mid-to-late 19th-century publicists was that an occupant could not alter the political order of territory”. Consistently, “[l]es États qui se font la guerre rompent entre eux les liens formés par le droit des gens en temps de paix; mais il ne dépend pas d’eux d’anéantir les faits sur lesquels repose ce droit des gens. Ils ne peuvent détruire ni la souveraineté des États, ni leur indépendance, ni la dépendance mutuelle des nations”. This was already confirmed by domestic and international practice contemporary to the occupa­tion of the Hawaiian Kingdom by the United States. For instance, in 1915, in a judgment concerning the case of a person who was arrested in a part of Russian Poland occupied by Germany and deported to the German ter­ritory without the consent of Russian authorities, the Su­preme Court of Germany held that an occupied enemy territory remained enemy and did not become national territory of the occupant as a result of the occupation.

Professor Lenzerini when on to state:

In light of the foregoing, it appears that the theories according to which the effective and consolidated occupation of a territory would determine the acquisition of sovereignty by the occupying power over that territory—although supported by eminent scholars—must be confuted. Consequently, under international law, “le transfert de souveraineté ne peut être considéré comme effectué judiquement que par l’entrée en vigueur du Traité qui le stipule et à dater du jour de cette mise en vigueur”, which means that “[t]he only form in which a cession [of territory] can be effected is an agreement embodied in a treaty between the ceding and the acquiring State. Such treaty may be through the outcome of peaceable negotiations or of war.” This conclusion had been confirmed, among others, by the US Supreme Court Justice John Marshall in 1928, holding that the fate of a territory subjected to military occupation had to be “determined at the treaty of peace.”

There is no treaty where the Hawaiian Kingdom ceded its territorial sovereignty to the United States. The American military occupation of the Hawaiian Kingdom is now at 131 years.